Drilling-machine.



No. 675,84l. Patented June 4, l90l. W. D. RICHTER.

DRILLING MACHINE.

(Application filed Mar. 28, 1961.

(No Model.)

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UNITED STATES PATENT OFFICE.

\VOLFGANG D. RICHTER, OF PHILADELPHIA, PENNSYLVANIA, ASSIGNOR TODOMESTIC MACHINERY \VORKS, OF SAME PLACE.

DRILLING-MACHINE.

SPECIFICATION forming part of Letters Patent No. 675,841, dated June 4,1901.

Application filed March 28, 1901. Serial No. 53,173. (No model.)

To all whom, it may concern.-

Be it known thatLWoLEoANo D. RICHTER, a citizen of the United States,residing at the city of Philadelphia, in the county of Philadelphia andState of Pennsylvania, have invented certain new and useful Improvementsin Drilling-Machines, of which the following is a specification.

My invention has relation to a drill to be operated mechanically; and insuch connection it relates to the construction and arrangement of thetool and of its operating-spindle.

Heretofore in this class of machines the tool-spindle having acentrally-arranged slot in which the tool was adapted to be secured waseither hollow above the tool to permit of the insertion and adjustmentof a bolt or screw for locking the tool to the spindle or else the slotof the tool-spindle was cut wider than the width of the tool to permitof the entrance of wedges to properly secure the tool when centered tothe spindle. In other words, it has been thought necessary in machinesof this character to center the tool manually and then look the tool inthe spindle.

The principal object of my invention is to provide in adrilling-machine, in conjunction with a rotating spindle having a rangeof vertical movement, a self-centering tool fitted into a slotdiametrically traversing the spindle, said tool having a range oftransverse movement in the slot to permit of its self-centering duringthe drilling operation and said tool not locked to the spindle.

The nature and scope of my invention will be more fully understood fromthe following description, taken in connection with the accompanyingdrawings, forming part hereof, in which- Figure 1 is a front elevationalview of a portion of a drilling-machine, illustrating a toolspindle andtool in operative position with respect to the work. Fig. 2 is anenlarged detail view of the lower end of the drill-spindle and of thetool, the work to be drilled being shown in section. Fig. 3 is a sideelevational view of the spindle and tool. Fig. 4 is a cross-sectionalview on the line 4 4 of Fig. 2, and Fig. 5 is a plan view of the cuttingedge of the tool.

Referring to the drawings, a represents the tool-spindle, adapted to berotated by suitable means (not shown) and to be fed vertically toward oraway from the table a of the machine by well-known mechanism (not shown)controlled by the hand-wheel a The table a has a bracket or extension ahaving an opening for the reception and guidance of the reduced end a ofthe spindle. The body a and reduced end a" of the spindle arediametrically slotted for the reception of the tool I); but otherwisethe spindle is solid. The tool b snugly fits in the slot of the spindle,so as to have no vertical play and but a slight transverse movementtherein. The cutting face or edge of the tool I) has a central flatportion 1) and oppositely-beveled end por tions Wand 11 The sides b ofthe tool I) are not flattened, but rounded on an arc of a circlecorresponding to the circular opening to be drilled. The cutting edgesof the tool I) are the beveled portions and Zr, which are not onlyoppositely beveled, but also of corresponding length and project acorresponding distance from the medial line of the tool.

Referring now to Fig. 2, if the toolb be loosely inserted in the slot ofthe spindle a, as indicated in dotted lines, with the center of the toolprojecting to one side of the center of the spindle, alarger portion ofthe cutting-surface b will engage the face of the work d to be drilledthan the surface will engage. The friction in excess upon that end ofthe tool carrying the surface b over the opposite end b will instantlycause the tool to shift in the slot of the spindle a as the spindlebegins to rotate. in this direction, the bight of the cutting-surface 11causes the tool to shift in an opposite direction and so on until thetool centers itself. In the drilling of the material d the tendency tochatter if the tool I) were fixed to the spindle and not properlycentered results simply in the proper centering of the tool, since theexcess of friction on one cutting-surface will shift the tool in theslot until the friction of both cutting-surfaces is equal. The holebored will therefore be more quickly and smoothly drilled, and thepreliminary work of centering the tool and looking or wedging it in thespindle is avoided. Again, by not hollowing out the spindle for Ifshifted too far the reception of a tightening bolt or screw and by notexcessively widening the slot in the spindle to permit of the use ofwedges the spindle will be immeasurably strengthened and will not soreadily break as was heretofore the case.

Having thus described the nature and object of my invention, what Iclaim as new,

/ and desire to secure by Letters Patent, is

in combination with a tool adapted to fit snugly in the slot of thespindle and free to move transversely therein, said tool having on itsunder or cutting edge two oppositelybeveledcutting-surfaces,substantially as and for the purposes described.

In testimony whereof I have hereunto set my signature in the presence oftwo subscribing witnesses.

WOLFGANG D. RICHTER.

Vitnesses:

J. WALTER DOUGLASS, THOMAS M. SMITH.

